How do I filter database entries with a textbox

Question

1.00/5 (1 vote)

See more:

I have a small project I am working on for my kid where he can add pokemon cards to his collection. It's just a C# windows Forms application connected to a SQL server database. I am trying to filter the entries in the database through a dataGridView using text entered in a textbox but it isnt filtering it. The entries just remain unfiltered in the dataGridView. Here is the code for the form.

What I have tried:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace JacobsPokedex
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        DataTable dt = new DataTable("Cards");

        private void Form1_Load(object sender, EventArgs e)
        {
            string connectionString = null;
            connectionString = "Data Source=DESKTOP-NU2DVAO\\SQLEXPRESS;Initial Catalog=Pokedex;Integrated Security=True";

            using (SqlConnection cnn = new SqlConnection(connectionString))
            {
                try
                {
                    cnn.Open();
                    using (SqlDataAdapter da = new SqlDataAdapter("select * from Cards", cnn))
                    {
                        da.Fill(dt);
                        dataGridView1.DataSource = dt;
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }
        }
 private void searchByNameTextBox_KeyPress(object sender, KeyPressEventArgs e)
         {
             if (e.KeyChar == (char)13)
             {
                 DataView dv = dt.DefaultView;
                 dv.RowFilter = "pokemon_name LIKE '" + searchByNameTextBox.Text + "%'";
                 dataGridView1.DataSource = dv;
             }
         } 

        private void openAddCardFormButton_Click(object sender, EventArgs e)
        {
            var AddCardForm = new AddCardForm();
            AddCardForm.Show();
        }
    }
}

I also tried this with TextChanged with same results

private void searchByNameTextBox_TextChanged(object sender, EventArgs e)
        {
            (dataGridView1.DataSource as DataTable).DefaultView.RowFilter =
            string.Format("pokemon_name LIKE '{0}%' OR pokemon_name LIKE '% {0}%'", searchByNameTextBox.Text);
        }

Posted 6-Oct-21 19:49pm

Chris Mouser

Updated 6-Oct-21 20:22pm

v2

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2021-10-06T20:06:00

It works fine for me using a DataView.RowFilter:

/// <summary>
/// A Filter changed - update the DataView
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void textBoxFilter_TextChanged(object sender, EventArgs e)
    {
    StringBuilder sb = new StringBuilder();
    AppendFilter(sb, "TrackName", tbTrackFilter.Text, "");
    AppendFilter(sb, "Band", tbBandFilter.Text, " AND ");
    AppendFilter(sb, "Album", tbAlbumFilter.Text, " AND ");
    dvFiles.RowFilter = sb.ToString();
    }

/// <summary>
/// Append this clause to the filter statement.
/// </summary>
/// <param name="filter">Filter so far assembled</param>
/// <param name="column">Name of column to add</param>
/// <param name="filterMatchText">Text to look for</param>
/// <param name="append">Prefix string if this clause is valid.</param>
private void AppendFilter(StringBuilder filter, string column, string filterMatchText, string append)
    {
    if (!string.IsNullOrWhiteSpace(filterMatchText))
        {
        // Remove quotes
        filterMatchText = filterMatchText.Replace("'", "''");
        if (filter.Length != 0)
            {
            filter.Append(append);
            }
        filter.AppendFormat(" [{0}] LIKE '%{1}%' ", column, filterMatchText);
        }
    }

So the chances are it's the KeyChar in your code that causes the problem.
Use the debugger, and put a breakpoint on the first line of your handler and step the code through to find out exactly what is happening.